Automatic dump for steam shovels



Aug. 12, 1930. G. THOMAS 1,773,066

AUTOMATIC DUMP FOR STEAM SHOVELS Filed March 6, 1929 2 Sheets-Shan 1 WW F Tf Aug. 12, 1930. G. THOMAS AUTOMATIC DUMP FOR STEAM SHOVELS F iled March 6, 92 2 Sheets-Shee 2 Patented Aug. 12, 1930 PATENT OFFICE GARFIELD THOMAS, OF OLD FORT, NORTH CAROLINA AUTOMATIC DUMP FOR STEAM SHOVELS Application filed March 6', 1929. Serial No. 344,778.

This invention relates to steam shovels or like excavating devices and particularly to the means for dumping buckets or dippers of steam shovels of this character. Ordi narily the rear end of the scoop or dipper is adapted to be unlatched and then swings outward or to open position under the gravity of the load to discharge the load. The latch is released by means of a dump rope as it is 1 called usually formed in sections, one of the sections being connected to the latch and at the other end to a lever and then a section leads from the lever over suitable pulleys to the operators cab where it is operated by hand. This hand dump has never been satisfactory for the reason that it does not work every time and sometimes as many as a dozen attempts have to be made before the latch can be released. This is due to the fact that at differentpositions of the bucket, the line is more or less slack, the dumping line having to be made of suflicient length to operate when the dipper is at its most extended position as well as when the dipper or scoop is disposed much nearer to the cab.

The general object of the present invention is to provide a structure which will automatically take up the dump line or rope and keep it at all times taut without regard to the position of the bucket or scoop.

It is also an object to provide means-whereby this dump line may be pulled to cause the retraction of the latch and opening of the bucket.

A further object is to provide a construction wherein the means for at all times keeping the dump rope taut consists of a spool or drum mounted in connection with the shaft of the pinion or gear wheel which operates upon the rack bar which supports the bucket.

A further object is to provide a tripping lever having a pulley engaging the bight of the dump rope and a steam cylinder having a manually actuatable valve and a piston connected to the tripping lever, the opening of the valve causing the piston to move in a direction to shift the lever to exert strain upon the dump rope and thus actuate the trip of the shovel.

Figure 3 is an end elevation thereof with the bed plate in section;

Figure 4 is a detailed view partly in elevation and partly in section of the winding drum and pulley;

Figure 5 is a detailed sectional view of the controlling valve.

Referring to the drawings, it will be seen that I have illustrated a portion of an ordinary steam actuated or motor actuated shovel, 10 designating the boom which extends outward from the cab 11 which is mounted upon endless tractors or upon wheels as desired. The boom 10 is of any ordinary or suitable construction and extending through the boom 10 is the shovel or scoop carrying bar 12carrying the scoop 13. The scoop 13 is raised or lowered, by means of a cable 14 passing over a sheave l5 and over a pulley 16 in the usual manner and passing to suitable operating drums and the boom 10 is raised or lowered by suitable cables and operating drums not specifically illustrated as all these parts are of any ordinary or suitable construction. The beam 12 which carries the shovel or scoop 18 is formed with a rack 17. This beam passes through the boom 10 and is engaged by a pinion mounted upon a shaft 18. This shaft 18 may be actuated in any suitable manner by power transmitted to the shaft in anydesired way, such means being commonly found in structures of this nature. The bottom or rear end of the shovel is mounted for swinging movement and to it is connected the dump rope section 19 which in turn is connected to a lever 20.

The lever 20 in turn is engaged by a dump rope section 21. So far I have described what is commonly found in devices of this character.

For the purpose of operating this dump as at Qiiand passesithmugh a bearing formed in an arm 28 which is cast and extends from the cylinder itself the piston rod being connected to the time end of the arm 26. Connected to the arm 26 between the piston rod 25 and the cranked portion is a rod 29 which extendsthrough a guide 30 and is surrounded by a coiled compression spring 31 which. bears against nuts 32 mounted upon the rod. When steam is admitted to the cylinder 22, the piston will be forced outward and the rod 29 will be shifted toward the left inF i ure 2 against the tension of the spring 31. f steam be released from the cylinder 22, the spring will cause the retraction of the lever and of the piston rod. The lever 26 at its upper end carriesupon it the pulley 33. 1 Entering the rear end of the cylinder is a steam ipe 34 controlled by a three-way valve 35. i e handle of this valve is connected to a. 8 ing 36 normally holding the valve closed an from the handle of the valve extends a eimtrolcable 37 which preferably, though not necessarily, extends to a foot controlled pedal 38 mounted within the cabin. *iWhen this pedal is depressed the valve is opened. The steam enters into the interior of.

the cylinder 22 forcing the piston toward the front end of the cylinder and causing a retractionof the pulley 33.

Mounted upon the shaft 18 and rotating with this shaft or attached to the pulley which forms part of this shaft is a winding drum-39 which carriesupon it a plate 40. Diwed in spaced relation to the plate 40 is a plate 40 and disposed between these plates is apulley mounted upon a bushing 51 in turn mounted upon a transverse bolt 52, the bushing acting as a spacer holding the plates 39 and apart so as to permit the pulley to have free rotation. A guard 41 extends over thepulley and is attached to the boom. The cable section 21 passes over the pulley 50 and then extends over the pulaley '33 on the levers 26. The cable then extends to the drum 39 upon which the cable is wound.

It will be seen-that with this construction, when the shaft 18 is rotated in a direction to cause the beam 12 to be forced outward, the drum 38 will pay out the cable so that there will be no strain upon the cable at 21. When the beam 12 is retracted by a reverse rotation of the shaft 18, the cable will'be correspondingly wound upon the drum so that there will be no slack in the cable and thus at all times during the operation of this M1 the cable will be kept taut.

Obviously, however, with the cable taut, when the treadle 38 is depressed and the steam is admitted to the cylinder, the lever 26 will be retracted, retracting the pulley 33 and placing strain upon the dumping cable.

Inasmuch as the dumping cable is kept taut at all times, it is obvious that the rearward movement of the .pulley 33 will cause a release of the latching means used to hold the bottom of the shovel closed and the shovel will dump. It will also be obvious that this release will be definite and positive in all positions of the bucket for the reason that there will be no slack in the cable 21 but that the cable is at all times taut.

I do not wish to be limited to the particular construction of the shovel as I have merely illustrated a standard shovel construction, nor do I wish to be limited to the exact construction of my dumping attachment as this might be modified in many ways without departing from the spirit of the invention as defined in the appended claims.

It will be seen that my device can be readily attached to a steam shovel already built or that my attachment may be built into a steam shovel in the first instance.

I claim Y 1. In a steam shovel, a boom, a dipper carrying beam, a dipper carried thereon and having a swinging bottom, a shaft on the boom operatively engaged with the beam to shift it longitudinally, a winding drum on said shaft and rotating therewith, means for tripping the dipper to discharge its contents including a tripping cable engaged at one end with the winding drum and adapted to be wound up thereon or unwound as the beam is shifted longitudinally, a steam cylinder, a piston operating therein, a bracket extending from the steam cylinder, a lever pivoted upon the bracket and connected at one end to the piston and carrying at its other end a pulley over which the tripping cable passes, the pulley engaging the cable in the length of the cable between the winding drum and the dipper, manually controllable means for admitting steam to the interior of the cylinder to thereby shift the lever and pulley in a direction to retract the cable and trip the bottom of the dipper, and a spring engaging the lever and acting to resist the movement of the lever under the outward movement of the piston and to return the piston to its initial position when steam pressure is released within the cylinder.

2. In a steam shovel, a boom, a dipper beam carrying a dipper and mounted on the boom, the dipper having a swingable bottom, a shaft on the boom operatively engaging the beam to shift it longitudinally in one direction or the other, a drum mounted on the shaft and rotating therewith, a pulley mounted upon the drum axially thereof, the pulley having free rotation independent of the .drum, a

cable operatively connected to the swingable bottom to trip it, an arm carrying a pulley, the cable passing over the first named pulley, then around the pulley carried on said arm and then extending to and being connected to the drum, and manually controllable means for shifting said arm to place strain upon the cable.

3. In a steam shovel, a boom, a dipper beam carrying a dipper and mounted on the boom, the dipper having a swingable bottom, a shaft on the boom operatively engaging the beam to shift it longitudinally in one direction or the other, a drum mounted on the shaft and rotating therewith, a pulley mounted upon the drum axially thereof, the pulley having free rotation independent of the drum, a cable operatively connected to the svvingable bottom to trip it, an arm carrying a pulley, the cable passing over the first named pulley, then around the pulley carried on said arm and then extending to and being connected to the drum. and manuallv controllable means for shifting said arm to place strain upon the cable, including a steam cylinder connected to a source of steam pressure, a piston operating therein and operatively connected to the arm to shift it, a valve controlling admission of steam to the cylinder or the venting of the steam therefrom, a manually controllable member for shifting said valve, and a spring acting to return the piston to its normal position when the valve has been shifted to a position venting the cylinder.

In testimony whereof I hereunto afiix my signature.

GARFIELD THOMAS. 

